| package system |
| |
| import ( |
| "io/ioutil" |
| "path/filepath" |
| "strconv" |
| "strings" |
| ) |
| |
| // look in /proc to find the process start time so that we can verify |
| // that this pid has started after ourself |
| func GetProcessStartTime(pid int) (string, error) { |
| data, err := ioutil.ReadFile(filepath.Join("/proc", strconv.Itoa(pid), "stat")) |
| if err != nil { |
| return "", err |
| } |
| return parseStartTime(string(data)) |
| } |
| |
| func parseStartTime(stat string) (string, error) { |
| // the starttime is located at pos 22 |
| // from the man page |
| // |
| // starttime %llu (was %lu before Linux 2.6) |
| // (22) The time the process started after system boot. In kernels before Linux 2.6, this |
| // value was expressed in jiffies. Since Linux 2.6, the value is expressed in clock ticks |
| // (divide by sysconf(_SC_CLK_TCK)). |
| // |
| // NOTE: |
| // pos 2 could contain space and is inside `(` and `)`: |
| // (2) comm %s |
| // The filename of the executable, in parentheses. |
| // This is visible whether or not the executable is |
| // swapped out. |
| // |
| // the following is an example: |
| // 89653 (gunicorn: maste) S 89630 89653 89653 0 -1 4194560 29689 28896 0 3 146 32 76 19 20 0 1 0 2971844 52965376 3920 18446744073709551615 1 1 0 0 0 0 0 16781312 137447943 0 0 0 17 1 0 0 0 0 0 0 0 0 0 0 0 0 0 |
| |
| // get parts after last `)`: |
| s := strings.Split(stat, ")") |
| parts := strings.Split(strings.TrimSpace(s[len(s)-1]), " ") |
| return parts[22-3], nil // starts at 3 (after the filename pos `2`) |
| } |